Users sometimes subscribe to a network service plan to access a network to perform a task using a user device. For example, the user may use the user device to access a web page, place a telephone call, communicate with another user device, or perform some other task (e.g., via the network). Network devices may authorize the user device to access the network based on subscription information associated with the user device. Network devices sometimes block access of user devices that do not have an associated subscription, thereby preventing the user device from accessing any services provided by the network, including a service that allows the user to place a telephone call to subscribe to the network service plan.